I don't think I would agree with you there bigjim. You can get parts for a used Mercedes! Plus, you can find mechanics who take pride in working on Mercedes. Let me know if you find one who brags about working on Kias!
If the tensioning wheel was bad or incorrectly tensioned, then it should have been noticed when the head gasket was replaced. You should not have had to share the cost of the repair, IMO.
Also, did you split the cost of the "retail" repair cost or the "dealer's" cost? If you paid half of the "retail" cost of the repair, it is possible you paid the entire cost of the repair. An old favorite trick of the less reputable dealers.
If you are a good "stick" driver, then it should not start slipping so badly in 1000 miles that the dealer would note that you have to replace it. A clutch usually starts slipping over a longer period of time in most cases, and I think should have been noted when the car was inspected if it was that bad. Of course, I don't know if you drive a clutch properly, just a comment from an old factory rep who has seen it all.
In the dealer's defense, I have to state that not noticing the clutch could have been an honest mistake on their part. However, once detected, within about 1000 miles, I feel it is their responsibility to fix it at no charge. (Assuming you are a good stick driver!). They shouldn't quibble about 50 extra miles!
I am also curious about whether they did any testing on the engine and cooling system since unless the engine was abused, or the coolant ran low, most head gaskets don't blow all of a sudden either. Most early symptoms of an impending HG failure are just not noticed by the drivers until it becomes a major failure. However, if a car is really gone over thoroughly, and fully tested, then I would not expect a head gasket to completely fail after such testing within 1000 miles or so.
The bad news is that few used car dealers lot's, even along side new car dealers, really do much to their used cars except the items which are really apparent to a prospective buyer. It is a matter of cost. Whether to spend the money to carefully test every car they sell or just fix the cars that fail? Thorough testing costs a lot of money.
Your choice to buy a Suby as a used car was, IMO, a better than average chance to get a good used car which, on average, is a better deal per dollar than most other brands. However, I do not recall the year and model you bought, it might make a difference, but that is true of all brands.
Check if you have a county or city Consummer Affairs Office? They might be able to help. In my area, they rule the used car dealers and help customers with cases like yours if they feel you got a bum deal.
The Ole Factory Rep (not Subaru)